/Engine/Source/Runtime/GeometryFramework/Public/Components/MeshRenderDecomposition.h
Build decomposition with one group for each MaterialID of mesh
static void BuildMaterialDecomposition ( const [FDynamicMesh3](API\Runtime\GeometryCore\DynamicMesh\FDynamicMesh3) * Mesh, const [FComponentMaterialSet](API\Runtime\InteractiveToolsFramework\TargetInterfaces\FComponentMaterialSet) * MaterialSet, [FMeshRenderDecomposition](API\Runtime\GeometryFramework\Components\FMeshRenderDecomposition) & Decomp )